JP2009282294A - Cleaning blade for electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning blade for an electrophotographic apparatus which has good cleaning performance, immediately after a long stoppage period under a low-temperature environment or during a continuous use under a low temperature environment, even in the case of using small-diameter spherical toner particles. <P>SOLUTION: The cleaning blade for the electrophotographic apparatus has an elastic blade member for removing the residual toner, while rubbing an image carrier in contact with the image carrier. The elastic blade member satisfies the following conditions (1) to (4); (1) stress relaxation modulus at 10°C shown by an expression (a): stress relaxation modulus=ä(stress variation when being neglected for one hour in a state where the blade is expanded by 10%)/(moment stress, when being expanded by 10%)}×100 is ≤25%, (2) international rubber hardness (IRHD) is in the range of 65 to 80, (3) stress when applying 100% tension in a tensile test is in a range of 3.0 to 5.0 MPa, (4) a tanδ peak temperature obtained by a dynamic viscoelasticity test is in a range of -20 to 0°C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cleaning blade used in an electrophotographic apparatus using an electrostatic transfer process such as an electrophotographic copying machine, a laser beam printer, and a facsimile machine.

  In an electrophotographic apparatus typified by a copying machine, a printer, a facsimile, etc., an electrostatic latent image formed by uniformly charging the outer peripheral surface of an image carrier such as a photoconductor and exposing through a copy image, Toner is attached to form a toner image, which is transferred to a transfer material such as paper to form an image. Since toner remains on the outer peripheral surface of the photoconductor after the toner image is transferred, the residual toner is removed by contacting and rubbing the cleaning blade against the outer peripheral surface of the photoconductor to prepare for the next image formation. ing.

  The cleaning blade is provided by integrating a rubber blade member at one end of a plate-like support fitting (holder) made of metal or the like, and fixing the holder to the apparatus. Since the blade member is excellent in mechanical strength such as wear resistance and has low creep properties such as permanent deformation due to contact stress, a polyester-based urethane elastomer, especially a thermosetting polyester-based urethane elastomer is used. Yes.

  The urethane elastomer is produced by a prepolymer method, a semi one-shot method, a one-shot method, or the like using a polyisocyanate, a polyol, a chain extender and a catalyst. For example, when manufacturing a cleaning blade by the prepolymer method, a prepolymer is prepared using a polyisocyanate and a polyol, a chain extender and a catalyst are added to the prepolymer, and this is then injected into a molding die. And cured.

  In order to completely remove the residual toner on the photoconductor with the cleaning blade, it is necessary that the contact of the blade member on the outer peripheral surface of the photoconductor is always kept constant. For this reason, methods are generally used in which the positional relationship between the cleaning blade and the photosensitive member is regulated, or the support fitting is pressed with a spring.

  However, if the hardness of the urethane elastomer blade is too high, there is a risk of damaging the abutting photoconductor, and if it is too low, the wear resistance will be insufficient and chipping will occur at the edge part, and the toner will slip through the defective part. Cleaning failure may occur.

In recent years, in order to increase the resolution of electrophotographic apparatuses, the diameter of toner used has been reduced and the shape of the toner has been made spherical. It is likely to occur. In addition, with the widespread use of electrophotographic copying machines and laser beam printers, they have been used in a wider range of environments than before, especially in low-temperature environments (10 ° C or lower), the urethane elastomer rubber used for blade members. Due to the decrease, cleaning failure tends to occur. Among them, cleaning failure is particularly likely to occur when used for the first time in the morning after being left overnight in a low temperature environment. The cleaning performance at a low temperature has a correlation with the peak temperature of tan δ, and the cleaning performance at a low temperature can be improved by setting the peak temperature of tan δ to be equal to or lower than the temperature assumed for the operating temperature of the electrophotographic apparatus. It has been reported (Patent Document 1). Further, it has been reported that the cleaning performance for spherical toner is improved by regulating the 300% modulus and tear strength (Patent Document 2). However, the cleaning blade of Patent Document 1 cannot be said to have a sufficient cleaning performance with respect to the small diameter and spherical toner accompanying the increase in image quality of the electrophotographic apparatus, and the cleaning blade of Patent Document 2 has a cleaning performance in a low temperature environment. Is not enough.
JP 11-212418 A JP 2002-72799 A

  An object of the present invention is to provide a cleaning blade for an electrophotographic apparatus having a good cleaning performance even when a small-diameter, spherical toner is used, immediately after being stopped for a long time in a low-temperature environment and during continuous use in a low-temperature environment. Is to provide.

The present invention is a cleaning blade for an electrophotographic apparatus having an elastic blade member that contacts and rubs against an image carrier to remove residual toner, and the elastic blade member satisfies (1) to (4). The present invention relates to a cleaning blade for an electrophotographic apparatus.
(1) The stress relaxation rate at 10 ° C. represented by the formula (a) is 25% or less.

(2) International rubber hardness (IRHD) is 65 or more and 80 or less (3) Stress at 100% tension in tensile test is 3.0 MPa or more and 5.0 MPa or less (4) tan δ in dynamic viscoelasticity test Peak temperature is -20 ° C or higher and 0 ° C or lower.

  The cleaning blade for an electrophotographic apparatus of the present invention has a good cleaning performance even when a small diameter, spherical toner is used, immediately after stopping for a long time in a low temperature environment and during continuous use in a low temperature environment.

The cleaning blade for an electrophotographic apparatus of the present invention is an electrophotographic apparatus cleaning blade having an elastic blade member for removing residual toner by abutting and rubbing against an image carrier, wherein the elastic blade member is (1) To (4).
(1) The stress relaxation rate at 10 ° C. represented by the formula (a) is 25% or less.

(2) International rubber hardness (IRHD) is 65 or more and 80 or less (3) Stress at 100% tension in tensile test is 3.0 MPa or more and 5.0 MPa or less (4) tan δ in dynamic viscoelasticity test Peak temperature is -20 ° C or higher and 0 ° C or lower.

  The elastic blade member (1) has a stress relaxation rate of 25% or less obtained from the formula (a) at 10 ° C. In the elastic blade member, when the stress relaxation rate represented by the formula (a) at 10 ° C. is 25% or less, the linear pressure at the edge of the elastic blade on the surface of the photosensitive member when left for a long time in a low temperature environment. Can be prevented, and the occurrence of poor cleaning can be suppressed.

  The value obtained by the following method can be adopted as the stress relaxation rate. A strip-shaped test piece having a thickness of 0.5 mm is cut out from the produced blade member, and this test piece is fixed to a stress measuring machine (TMA / SS 6000: manufactured by Seiko Instruments Inc.) so that the measurement length is 10 mm. The internal environment of the cavity is set to 10 ° C., a displacement of 1 mm is applied, and this is held for 60 minutes. The stress at the moment when the displacement is applied and the stress after 60 minutes are measured, and the stress relaxation rate is calculated from the measured value according to the equation (a).

  The elastic blade member has (2) international rubber hardness (IRHD) of 65 or more and 80 or less. In the elastic blade member, if the hardness is 65 ° (IRHD) or more, the toner can be prevented from slipping out, and if the hardness is 80 ° (IRHD) or less, the wear of the photoreceptor can be suppressed. .

  As the international rubber hardness (IRHD), a measurement value according to a measurement method based on JIS K6253 can be adopted using a hardness meter manufactured by Wallace Corporation.

  The elastic blade member (3) has a stress (M100) at 100% tension in a tensile test of 3.0 MPa or more and 5.0 MPa or less. In the elastic blade member, when M100 is 3.0 MPa or more, the linear pressure of the edge portion applied to the surface of the photoreceptor is sufficient, the deformation of the edge portion can be suppressed, the toner slips and the edge portion is missing. It is possible to suppress the occurrence of cleaning failure due to. If M100 is 5.0 MPa or less, it is possible to suppress an excessive increase in the linear pressure at the edge portion on the surface of the photoreceptor, and it is possible to suppress the occurrence of wear on the edge portion and the surface of the photoreceptor.

  For the stress at the time of 100% tension in the tensile test, a measured value by a measuring method based on JIS K6251 can be adopted using a tensile tester (Unitron TS-3013: manufactured by Ueshima Seisakusho).

  In the elastic blade member, (4) the peak temperature of tan δ in the dynamic viscoelasticity test is −20 ° C. or higher and 0 ° C. or lower. If the tan δ peak temperature in the dynamic viscoelasticity test is −20 ° C. or higher, it is possible to suppress wear due to the extreme movement of the edge, and if it is 0 ° C. or lower, during continuous use in a low temperature environment. In this case, it has sufficient elasticity and can suppress the occurrence of poor cleaning in a low temperature environment.

  As the tan δ peak temperature, a measurement value obtained by the following measurement method can be adopted. A strip-shaped test piece is cut out from the blade member, and this test piece is fixed to a dielectric loss measuring machine (DMS6100: manufactured by Seiko Instruments Inc.) so that the measurement length is 20 mm. The test piece is distorted at an amplitude of 5 μm and a frequency of 10 Hz, and tan δ from −30 ° C. to 60 ° C. is measured every about 0.5 ° C. at a temperature rising speed of 2 ° C./min. The temperature at which the value of tan δ becomes maximum is taken as the peak temperature of tan δ.

  By satisfying (1) to (4), the elastic blade member has good cleaning performance in a low temperature environment even when a small particle size and spherical toner is used.

  The elastic blade member is preferably formed using a urethane elastomer material.

  Such a urethane elastomer material is preferably a liquid composition containing a polyisocyanate, a polyol, a chain extender and a urethane curing catalyst.

  As said polyisocyanate, what is necessary is just to have two or more isocyanate groups, for example, the following can be mentioned. 4,4'-diphenylmethane diisocyanate (MDI), isophorone diisocyanate, 4,4'-dicyclohexyl diisocyanate. Trimethylhexamethylene diisocyanate, tolylene diisocyanate, carbodiimide-modified diisocyanate, polymethylene phenyl polyisocyanate. Orthotoluidine diisocyanate, naphthalene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, paraphenylene diisocyanate, lysine diisocyanate methyl ester, dimethyl diisocyanate and the like. These may be used alone or in combination of two or more. Among these, 4,4′-diphenylmethane diisocyanate (MDI) can be mentioned as a preferable one.

  As a polyol used with the said polyisocyanate, what is necessary is just to have a 2 or more hydroxyl group, for example, the following can be mentioned. Polyethylene adipate polyester polyol, polybutylene adipate polyester polyol, polyhexylene adipate polyester polyol, polyethylene-propylene adipate polyester polyol. Adipate-based polyester polyols such as polyethylene-butylene adipate polyester polyol and polyethylene-neopentylene adipate polyester polyol. Polyether polyols such as polycaprolactone polyester polyol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol obtained by ring-opening polymerization of caprolactone. Polycarbonate diol etc. These may be used alone or in combination of two or more.

  The chain extender may be any one that can extend the urethane elastomer chain, and a polyol can be used. Specifically, the following can be mentioned. 1,4-butanediol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, xylylene glycol. Polyols having a molecular weight of 200 or less, such as triethylene glycol, trimethylolpropane, glycerin, pentaerythritol, sorbitol, 1,2,6-hexanetriol.

  The urethane curing catalyst is roughly classified into an isocyanurate-forming catalyst and a urethanization catalyst, and any one of them may be used, but it is preferable to use the isocyanurate-forming catalyst and the urethanization catalyst in combination. As the urethane curing catalyst, amine compounds such as tertiary amines, organometallic compounds, and the like can be used. Specific examples include the following. Examples of the isocyanuration catalyst include tertiary amines such as N-ethylpiperidine, N, N'-dimethylpiperazine, N-ethylmorpholine. Tetraalkylammonium hydroxides and organic weak acid salts such as tetramethylammonium, tetraethylammonium and tetrabutylammonium. Hydroxyalkylammonium hydroxides and organic weak acid salts such as trimethylhydroxypropylammonium and triethylhydroxypropylammonium. Alkali metal salts of carboxylic acids such as acetic acid, propionic acid, butyric acid, caproic acid, capric acid, valeric acid, octylic acid, myristic acid, naphthenic acid. These may be used alone or in combination of two or more. Among these, alkali metal salts of carboxylic acid are preferable because they can suppress bloom after molding and can suppress contamination of other parts.

  As the urethanization catalyst, a commonly used catalyst for polyurethane curing can be used, and examples thereof include a tertiary amine catalyst. Amino alcohols such as dimethylethanolamine, N, N, N'-trimethylaminopropylethanolamine; Trialkylamines such as triethylamine. Tetraalkyldiamines such as N, N, N ′, N′-tetramethyl-1,3-butanediamine. Triethylenediamine, piperazine, triazine, etc. Moreover, the metal catalyst used for a shaping | molding of a polyurethane may be sufficient, and a dibutyl tin dilaurate etc. can be illustrated. These may be used alone or in combination of two or more. Of these, aminoalcohol is preferable because it is reactive, can suppress bloom after molding, and can suppress contamination of other parts, and more preferably N, N-dimethylaminohexanol.

  The amount of the isocyanurate-forming catalyst used is preferably 0.01% by mass or less based on the total mass of the polyol and the polyisocyanate. If the isocyanurate-forming catalyst is 0.01% by mass or less, it is possible to suppress an increase in isocyanate and an excessive stress relaxation rate.

  In the urethane elastomer material, the polyol is preferably 150 parts by mass or more and 300 parts by mass or less, and the chain extender is preferably 10 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polyisocyanate. Moreover, it is preferable that the usage-amount of the catalyst for urethane hardening is 0.02 mass% or more and 0.05 mass% or less with respect to the total mass of a urethane elastomer material.

  The urethane elastomer material may contain additives such as a catalyst, a pigment, a plasticizer, a waterproofing agent, an antioxidant, an ultraviolet absorber, and a light stabilizer as necessary.

  In order to produce an elastic blade member using such a urethane elastomer material, a prepolymer method, a one-shot method, a semipolymer method, a pseudo-prepolymer method, or the like can be used. As an example, a molding method using the prepolymer method will be described below.

  First, a cleaning blade mold is prepared, and a holder to be a support member is disposed. Next, a prepolymer obtained by mixing polyisocyanate and polyester polyol and partially polymerized in advance, a urethane curing catalyst and a chain extender are put into a casting machine, and stirred in a mixing chamber to obtain a liquid mixture. . This is injected into the mold, reacted and cured, and then the cured product is removed from the mold and cut into a predetermined size to produce a cleaning blade in which an elastic blade member made of polyurethane elastomer is molded on the holder. be able to. It is preferable to apply an adhesive to the portion of the holder where the elastic blade member is molded.

  In the above method, the method of forming the elastic blade member in which the holder is disposed in the mold is described. However, the elastic blade member may be molded and then bonded to the holder without arranging the holder in the mold.

In the elastic blade member obtained from the urethane elastomer material,
(5) Polyisocyanate concentration is 0.95 mmol / g or more and 1.15 mmol / g or less (6) Chain extender concentration is 0.25 mmol / g or more and 0.50 mmol / g or less (7) Urethane The group concentration is preferably 1.50 mmol / g or more and 1.80 mmol / g or less.

  When the elastic blade member has a polyisocyanate concentration of (5) 0.95 mmol / g or more, the hard segment amount in the urethane elastomer becomes sufficient and is suppressed from becoming soft, and satisfies the above conditions (1) to (4). . On the other hand, if the polyisocyanate concentration is 1.15 mmol / g or less, the hard segment amount is excessive and the hardness is prevented from becoming high, and the above conditions (1) to (4) are satisfied.

  If the elastic blade member (6) has a chain extender concentration of 0.25 mmol / g or more, the amount of hard segments in the urethane elastomer becomes sufficient and is suppressed from becoming soft, and the above conditions (1) to (4) Meet. On the other hand, if the concentration of the chain extender is 0.50 mmol / g or less, the hard segment amount is excessive and the hardness is suppressed, and the above conditions (1) to (4) are satisfied.

  If the elastic blade member (7) has a urethane group concentration of 1.50 mmol / g or more, aggregation between molecular chains is sufficient and the softening is suppressed, and the above conditions (1) to (4) are satisfied. On the other hand, when the concentration of the urethane group is 1.80 mmol / g or less, aggregation between molecular chains is excessively prevented from becoming high hardness, and the above conditions (1) to (4) are satisfied.

  The polyisocyanate concentration and the chain extender concentration in the blade member can be determined by the following formulas (b) and (c) by determining the number of moles based on the charged amount (g) and the molecular weight. The urethane group concentration can be determined by the following formula (d) from the number of hydroxyl groups of the polyol and chain extender determined by the following formulas (e) and (f). The measured value obtained by the measuring method according to JISK1557-1 can be adopted for the hydroxyl value of the polyol.

  An example of the cleaning blade for an electrophotographic apparatus of the present invention is shown in FIG. The cleaning blade for an electrophotographic apparatus shown in FIG. 1 has a blade member 150 of the present invention attached to a metal holder (rigid plate) 130. The formation position and shape of the blade member in the cleaning blade for an electrophotographic apparatus can be appropriately selected so that the blade member can come into contact with the photosensitive drum.

  The cleaning blade for an electrophotographic apparatus of the present invention is used in an electrophotographic apparatus using an electrostatic transfer process such as a copying machine, a laser beam printer, an LR printer (LED printer), a facsimile machine, an electrophotographic plate making system, and the like. It is done. In these apparatuses, a plurality of members such as an image carrier, a charging member, and a developing member can be integrally incorporated in addition to the cleaning blade, and the process cartridge can be applied to the main body of the electrophotographic apparatus.

  As an example of an electrophotographic apparatus to which the cleaning blade for an electrophotographic apparatus of the present invention is applied, the one shown in FIG. 2 can be exemplified. In the image forming apparatus shown in FIG. 2, an image carrier 51 such as a photosensitive member is rotationally driven around the support shaft in the clockwise direction in the drawing at a predetermined peripheral speed. The surface of the image carrier 51 is uniformly charged to a predetermined polarity and potential by a charging member 52 such as a corona discharger or a charging roller. The surface of the image carrier 51 that has been uniformly charged is then subjected to exposure of target image information (laser beam scanning exposure, slit exposure of a document image, etc.) by the exposure means L, and a static image corresponding to the target image information. An electrostatic latent image 53 is formed. Then, the electrostatic latent image 53 is sequentially visualized as a toner image by the developing member 54.

  The toner image formed on the surface of the image carrier 51 is then transferred to the surface side of the transfer material P by the transfer member 55. The transfer material P is conveyed from a paper supply unit (not shown) to the transfer portion between the image carrier 51 and the transfer member 55 at an appropriate timing in synchronization with the rotation of the image carrier 51. The transfer member 55 may be a roller type. In addition, in a color LBP that outputs a color image using four color toners, the color image of each color is sequentially transferred onto an intermediate transfer member such as a roller or a belt, and then transferred to the surface side of the transfer material P. Is done. The transfer material P that has received the transfer of the toner image is separated from the image carrier 55, is subjected to image fixing by a fixing member 58 such as a heat fixing roller, and is output as an image formed product.

  After the transfer, the surface of the image carrier 51 is cleaned by the electrophotographic apparatus cleaning blade 56 according to the present invention to remove the adhered contaminants such as residual toner, and is repeatedly used for image formation.

  Next, the cleaning blade for an electrophotographic apparatus of the present invention will be described in more detail with reference to examples, but the technical scope of the present invention is not limited to these examples.

[Example 1]
[Preparation of urethane elastomer material]
(A) 4,4′-diphenylmethane diisocyanate (MDI) and (B) polybutylene adipate polyester polyol (PBA, number average molecular weight 2000) are mixed in the ratio shown in Table 1, and reacted at 80 ° C. in a nitrogen atmosphere for 120 minutes. To obtain a prepolymer. On the other hand, (C) 1,4-butanediol (1,4-BD) and trimethylolpropane (TMP), (D) polyhexylene adipate polyester polyol (PHA, number average molecular weight 1000) and (E) catalyst, It mixed in the ratio shown in Table 1, and the hardening | curing agent was obtained.

  The molecular weight of the polyol in the prepolymer and the curing agent was determined by the following method. For monodisperse polystyrene for gel permeation chromatography (GPC), a calibration curve between the peak count and the number average molecular weight of the monodisperse polystyrene was prepared by GPC under the following conditions. Column: G3000PWXL × 2 (manufactured by Tosoh Corporation), elution solvent: 20 mM phosphate buffer, detector: differential refractometer, flow rate: 0.5 mL / min, sample solution usage: 10 μL, column temperature: 45 ° C. . The average molecular weight was calculated from the obtained calibration curve.

[Manufacture of cleaning blade for electrophotographic apparatus]
A holder was prepared as a support member in advance, and an adhesive was applied to one end surface. The above-mentioned holder was placed in a cleaning blade mold composed of an upper mold and a lower mold so that one end portion to which an adhesive was applied protruded into the cavity, and the prepared urethane elastomer material was injected into the cavity. This was subjected to reaction curing at a heating temperature of 130 ° C., and then the cured product was removed from the mold and cut into a predetermined size, whereby a cleaning blade for an electrophotographic apparatus having an elastic blade member formed on a holder was produced.

  With respect to the obtained cleaning blade, the stress relaxation rate, hardness, 100% modulus in tensile test, and tan δ peak temperature were measured by the above methods. The results are shown in Table 3.

The unit of numerical values in the table is parts by mass, and the symbols indicate the following.
MDI: 4,4′-diphenylmethane diisocyanate (Millionate MT: manufactured by Nippon Polyurethane Industry Co., Ltd.)
PBA: Polybutylene adipate polyester polyol (Nipporan 4010: manufactured by Nippon Polyurethane Industry Co., Ltd.)
1,4-BD: 1,4-butanediol (manufactured by Mitsubishi Chemical Corporation)
TMP: Trimethylolpropane (Mitsubishi Gas Chemical Co., Ltd.)
PHA: Polyhexylene adipate polyester polyol (Nipporan 164: manufactured by Nippon Polyurethane Industry Co., Ltd.)
Urethane catalyst (Kaorizer No. 25: Kao Corporation)
Nurate catalyst (P15: Air Products Japan)
[Evaluation of actual machine]
The obtained cleaning blade for an electrophotographic apparatus was incorporated into a laser beam printer (LBP-2510: manufactured by Canon Inc.), cleaned for a long time, and formed continuously 500 times at a low temperature (10 ° C.) (30%). The cleaning property was evaluated. A case where no defective image due to a cleaning failure was observed was indicated by 〇, a case where a slight image failure was observed was indicated by Δ, and a case where a remarkable image failure was observed was indicated by ×. The results are shown in Table 3.

[Examples 2 to 4, Comparative Examples 1 to 3]
A cleaning blade for an electrophotographic apparatus was prepared and evaluated in the same manner as in Example 1 except that the prepolymer and the curing agent were used in the ratios shown in Tables 1 and 2. The results are shown in Tables 3 and 4.

As shown in Tables 3 and 4, in Examples 1 to 4, no cleaning failure occurred after stopping for a long time and after printing 500 sheets. On the other hand, in Comparative Example 1, since the stress relaxation rate was large, a sufficient contact pressure could not be obtained after a long time stop at a low temperature, and cleaning failure occurred. Further, since M100 in the tensile test was larger than 5.0 MPa, an image defect occurred due to abrasion of the photosensitive drum surface. In Comparative Example 2, since the peak temperature of tan δ was high, the rubber property at low temperature was insufficient, and defective cleaning occurred. In Comparative Example 3, since the value of M100 in the tensile test was 3.0 MPa or less, the contact pressure necessary for cleaning could not be obtained, and cleaning failure occurred.

It is a side view showing an example of a cleaning blade for an electrophotographic apparatus of the present invention. 1 is a schematic configuration diagram showing an example of an electrophotographic apparatus to which a cleaning blade for an electrophotographic apparatus of the present invention can be applied.

Explanation of symbols

130 Holder 150 Blade member

Claims (4)

A cleaning blade for an electrophotographic apparatus having an elastic blade member that contacts and slides on an image carrier to remove residual toner,
The cleaning blade for an electrophotographic apparatus, wherein the elastic blade member satisfies (1) to (4).
(1) Stress relaxation rate at 10 ° C. represented by formula (a) is 25% or less

(2) International rubber hardness (IRHD) is 65 or more and 80 or less (3) Stress at 100% tension in tensile test is 3.0 MPa or more and 5.0 MPa or less (4) tan δ in dynamic viscoelasticity test Peak temperature is -20 ° C or higher and 0 ° C or lower.   2. The cleaning blade for an electrophotographic apparatus according to claim 1, wherein the elastic blade member is formed using a urethane elastomer material. 3. The cleaning blade for an electrophotographic apparatus according to claim 2, wherein the elastic blade member satisfies (5) to (7).
(5) Polyisocyanate concentration is 0.95 mmol / g or more and 1.15 mmol / g or less (6) Chain extender concentration is 0.25 mmol / g or more and 0.50 mmol / g or less (7) Urethane The group concentration is 1.50 mmol / g or more and 1.80 mmol / g or less.   The cleaning blade for an electrophotographic apparatus according to claim 3, wherein the polyisocyanate is 4,4'-diphenylmethane diisocyanate.

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